Conventionally, there has been provided a stator having a stator core including a plurality of stacked electromagnetic steel sheets (see Japanese Patent Publication No. 3586145 A). This stator core has a caulking portion for fixing the plurality of electromagnetic steel sheets with one another, and a plurality of slot portions opened toward the inner circumference side and arrayed along the circumferential direction. The number of the caulking portions is larger than that of the slot portions.